1. Field of the Invention
The present invention relates to a system and method for retrieving the geographic position of a mobile station in a radio telecommunication network.
2. Description of the Prior Art
Nowadays, the mobility of a mobile subscriber is an important issue in a radio telecommunication network. It is essential that services for which a mobile station (MS) user has subscribed in his home network follow him whenever he roams in a network or hands off to another network. The mobility issue is well known in the art and described in a plurality of standards such as in the American National Standards Institute (ANSI). The ANSI-41 protocol defines the MS geographic position retrieval for a roaming subscriber. This allows providing a MS geographic position to service applications (SA) such as law enforcement, emergency services (e.g. 9-1-1 calls) and location-based services.
However, before providing the MS geographic position to service applications, an implementation of a MS location functionality has to be done in the radio telecommunication network. In a radio telecommunication network that follows the ANSI-41 protocol, a mobile switching center (MSC) provides and sends geographic location data of the MS to a mobile positioning center (MPC). A position determining entity (PDE) then calculates the geographic position of the MS by using geographic location data sent by the MSC. The MPC stores that geographic position and renders it available to authorized network entities.
Today, with the introduction of several service applications and various systems, it can be difficult for network operators to provide a high level of security. Consequently a mobile subscriber's privacy is questionable. It is described in a plurality of standards that a mobile subscriber is allowed to restrict the access to his geographic position. More particularly, in the ANSI-41 protocol a subscriber can activate/deactivate the presentation of his position. As an example, Location Information Restriction (LIR) restricts presentation of a MS position information in a radio telecommunication network.
There are two different aspects regarding the control of a mobile subscriber on his location information privacy. In a first aspect, the MS geographic position can be retrieved with the approbation of the MS user. A MS user can authorize a network operator or a service provider for retrieving his geographic position upon subscribing to available and offered services (e.g. location-based services) in his home network. In a secondary aspect, the MS geographic position can be retrieved without the approbation of the MS user (law enforcement or emergency services (e.g. 9-1-1 calls)). As known today, a plurality of governments from different countries have adopted laws regarding the implementation of these service applications in radio telecommunication networks.
Then, in a way to restrict the access to a mobile subscriber's location, it is necessary to make sure that the MS geographic position is requested by an approved network entity. It is essential for a network operator to certify that the network entity is therefore one that is authorized to ask for the MS geographic position. Consequently, there is a need to improve the security aspect related to geographic positioning of mobile stations and the providing of such information to service applications. The present invention provides a solution to this effect.